Variable pedal driving device of bicycle

ABSTRACT

A variable pedal driving device for a bicycle, the device allowing the bicycle pedals to slide along crankshafts during operation of the device. Each pedal is coupled to a slide pipe slidably mounted on a crankshaft. The slide pipe is in turn connected to an eccentric member mounted on the main shaft of the driving device. When a pedal is driven in a forward direction, the eccentric member causes the pedal to extend out to a maximum distance from the main shaft, for more efficient driving of the bicycle.

This application is the national phase under 35 U.S.C. §371 of prior PCTInternational Application No. PCT/KR97/00284 which has an Internationalfiling date of Dec. 31, 1997 which designated the United States ofAmerica, the entire contents of which are hereby incorporated byreference.

TECHNICAL FIELD

The present invention relates to a bicycle, and more particularly, to avariable pedal driving device of bicycle which can extend, upon running,a distance between crankshafts which transmit a rotating force of pedalsto a rear wheel and the pedals to thereby obtain a maximum drivingenergy, at the expense of a minimum physical energy consumption.

BACKGROUND ART

Generally, an existing bicycle has been designed to have a fixeddistance between crankshafts and pedals and therefore, its running forcedepends only upon a driving force of the pedals assembled with thecrankshafts. Under such the driving structure of the bicycle, since therotating force of the pedals is exerted within a predetermined rotaryradius, the bicycle needs lots of driving energy upon running up aclimbing road. To improve this problem as well as to obtain an effectivedriving energy, it is well known that a change gear may be installed tooptimize the running force of the bicycle.

However, although the change gear has been mounted, the pedals, whichare a power source of the running force of the bicycle, maintains aconstant rotary radius to thereby provide the same driving energyamount. It can be therefore appreciated that installation of the changegear fails to provide a desired driving force. Due to such the failure,there occurs a need to vary the restrictive rotary radius of pedals tothereby optimize the running force of the bicycle in order to minimizedriving energy consumption.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a variable pedaldriving device of a bicycle which can improve a structural feature ofcrankshafts on which pedals are installed to enlarge a rotary radius ofthe pedals, upon running, thus to obtain an optimum driving energy andto minimize physical energy consumption, whereby when the bicycle runsup a climbing road or a long distance, it causes minimum fatigue to auser.

To achieve this and other objects according to the present invention, avariable pedal driving device of a bicycle includes: first and secondpower transmission units installed on both sides of a main shaft mountedon a shaft pipe of a shaft hole of a bicycle frame; first and secondslide pipes associated on first and second fixed shafts of first andsecond rotary levers rotatably mounted on both ends of the shaft pipe;first and second pedals installed on front ends of the first and secondslide pipes; and first and second crankshafts mounted on first andsecond rotary shafts of the power transmission units and slidinglyassociated on first and second slide holes of the first and second slidepipes, the first and second rotary shafts of the crankshafts and themain shaft being engaged with each other and the second rotary shaft ofthe second power transmission unit being engaged with a chain sprocketconnected by means of a chain with a rear wheel.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

FIG. 1 is a side view illustrating a variable pedal driving deviceconstructed according to a first embodiment of the present invention;

FIG. 2 is a perspective view illustrating main parts of FIG. 1;

FIG. 3 is a sectional view of FIG. 1;

FIG. 4 is an exploded perspective view of FIG. 1;

FIGS. 5A to 5C are side views illustrating operational states of FIG. 1;

FIG. 6 is an exploded perspective view illustrating a variable pedaldriving device constructed according to a second embodiment of thepresent invention;

FIG. 7 is a sectional view illustrating an assembling state of FIG. 6;

FIGS. 8A to 8C are side views illustrating operational states of FIG. 6;and

FIGS. 9A and 9B are sectional views illustrating main parts of FIG. 6.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a side view illustrating a variable pedal driving deviceconstructed according to a first embodiment of the present invention,FIG. 2 is a perspective view illustrating main parts of FIG. 1, and FIG.3 is a sectional view of FIG. 1. Furthermore, FIG. 4 is an explodedperspective view of FIG. 1, and FIGS. 5A to 5C are side viewsillustrating operational states of FIG. 1.

The present invention is characterized by that the distance betweencrankshaft 5 and 5' and pedals 7 and 7' which are each installed opposedat an angle of 180° to each other on a shaft hole 2 of a bicycle body'sframe 1 is adapted to be varied and extended during running.

Now, an explanation on the construction of a variable pedal drivingdevice constructed according to a first embodiment of the presentinvention will be in detail discussed hereinafter.

A shaft pipe 3 is assembled on the shaft hole 2 of the frame 1 andcoupling holes 41 and 41' of rotary levers 4 and 4' are rotatablyassembled on both sides of the shaft pipe 3. A main shaft 10 isinstalled on the inner side of the shaft pipe 3 and power transmissionunits 6 and 6' and crankshafts 5 and 5' are respectively installed onthe both sides of the main shaft 10.

The rotary levers 4 and 4' and the crankshafts 5 and 5' on both sides ofthe shaft pipe 3 are installed opposed to each other and the powertransmission units 6 and 6' between the rotary levers 4 and 4' and thecrankshafts 5 and 5' are under the same structure.

On either ends of the main shaft 10 installed on the inner side of theshaft pipe 3, differential tooth wheels 63 and 63' of the powertransmission units 6 and 6' are installed via the coupling holes 41 and41'. Since each of the power transmission units 6 and 6' takes aseparatable shape, cases 65 and 65' are designed to be separated fromeach other by means of assembling bolts 66 and 66'. The differentialtooth wheels 63 and 63' installed on the main shaft 10 and driving toothwheels 62 and 62' are installed on the interior of the powertransmission units 6 and 6'. In this case, the differential tooth wheels63 and 63' and the driving tooth wheels 62 and 62' are each connected toeach other by means of chains 67 and 67'.

The driving tooth wheels 62 and 62' are installed on rotary shafts 61and 61' of the cases 65 and 65', and the crankshafts 5 and 5' arefixedly assembled on the one ends of the rotary shafts 61 and 61' bymeans of fixing nuts 52 and 52'. Slide pipes 8 and 8' on which pedals 7and 7' are mounted are assembled on fixed shafts 42 and 42' installed onthe front sides of the rotary levers 4 and 4', and the crankshafts 5 and5' are inserted into slide holes 81 and 81' of the slide pipes 8 and 8'.

Meanwhile, a coupling pipe 91 is formed on one side of the shaft pipe 3,and a chain sprocket 9, which is connected by means of a chain 17 with arear wheel 15, is rotatably installed as a unitary body on the couplingpipe 91. A rotary tooth wheel 12 is fixedly assembled on the chainsprocket 9, which is connected by means of a chain 13 with a driventooth wheel 11 of the rotary shaft 61' having the differential toothwheel 63' of the one side case 65'.

The power transmission units 6 and 6' may be welded to be assembled onthe shaft pipe 3 of the shaft hole 2 of the frame 1, but to be easilyseparated and/or assembled, form male screw pipes 64 and 64' protrudedlytoward the interior of the cases 65 and 65'. Thus, the male screw pipes64 and 64' are screw-assembled with female screws 31 and 31' of theshaft pipe 3 by passing through the coupling holes 41 and 41' of therotary levers 4 and 4' and the coupling pipes 91 of the chain sprocket9.

In the power transmission units 6 and 6' the rotary shafts 61 and 61' onwhich the crankshafts 5 and 5' are installed are disposed on the rearwheel 15, such that when the pedals 7 and 7' assembled on the slidepipes 8 and 8' are driven in a forward direction, the crankshafts 5 and5' which are inserted into the slide holes 81 and 81' of the slide pipes8 and 8' are slided. As a result, the distance between the rotary shafts61 and 61' and the pedals 7 and 7' is extended at its maximum. On theother hand, when the pedals 7 and 7' are driven to the rear wheel 16,the length of the crankshafts 5 and 5' is reduced to its originallength.

FIG. 6 is an exploded perspective view illustrating a variable pedaldriving device constructed according to a second embodiment of thepresent invention, FIG. 7 is a sectional view illustrating an assemblingstate of FIG. 6, and FIGS. 8A to 8C are side views illustratingoperational states of FIG. 6.

Power transmission units 60 and 60' and crankshafts 50 and 50' arerespectively installed on the both sides of a main shaft 10a which isinstalled on the inner side of a shaft pipe 3a on a shaft hole 2 of aframe 1.

In the power transmission units 60 and 60' circular disks 601 and 601'on the main shaft 10a at the outside of the shaft pipe 3a areeccentrically installed on the rear wheel 15, and guide reentrant holes603 and 603' are formed on the circular disks 601 and 601', on whichguide members 604 and 604' having ball bearings 605 and 605' installedon the interior thereof are slidingly assembled. Slide pipes 80 and 80'having pedals 70 and 70' installed on the front sides thereof areassembled on hinge shafts 606 and 606' of the guide members 604 and604'.

The crankshafts 50 and 50', which are fixedly assembled on the both endsof the main shaft 10a, are slidingly inserted into the slide holes 801and 801' of the slide pipes 80 and 80'. Shaft holes 501 and 501' of thecrankshafts 50 and 50' are inserted on the both ends of the main shaft10a, such that the crankshafts 50 and 50' are fixedly assembled on themain shaft 10a by means of fixing nuts 502 and 502'.

Reentrant portions 602 and 602' are formed on the circular disks 601 and601' and a driving tooth wheel 607 is installed on the main shaft 10a ofthe reentrant portions 602 and 602' and is engaged with a differentialtooth wheel 608 on the one side thereof. A driven tooth wheel 609 on acoaxial line of the inside of the circular disk 601' is engaged with thedifferential tooth wheel 608, and the driven tooth wheel 609 is engagedwith rotary tooth wheels 901 and 901' of the chain sprocket 90 assembledon the shaft pipe 3a.

The differential tooth wheel 608, which is engaged with the drivingtooth wheel 607 of the circular disks 601 and 601' eccentricallyinstalled on the main shaft 10a, is installed on a front wheel 14a, suchthat when the pedals 70 and 70' are driven in a forward direction, thedistance between the crank shafts 50 and 50' which are slidinglyassembled on the slide pipes 80 and 80' and the pedals 7 and 7' isextended at its maximum. On the other hand, when the pedals 70 and 70'are driven to the rear wheel 15, the length of the crankshafts 50 and50' is reduced to its original length.

Preferably, a cover C is assembled on the reentrant portions 602 and602' of the circular disks 601 and 601' to thereby protect the mainshaft 10a, the driving tooth wheel 607 and the differential tooth wheel608.

The ball bearings 605 and. 605' installed on the interior of the guidemembers 604 and 604' are embodied in various assembling manners, asshown in FIGS. 9A and 9B. Firstly, as shown in FIG. 9A, a plurality ofball bearings 605 and 605' are installed on the guide members 604 and604', such that they are slidingly assembled in a circulated manner onthe guide reentrant holes 603 and 603'. On the other hand, as shown inFIG. 9B, slide protrusions 605a and 605a' are formed as a unitary bodyon the guide members 604 and 604', such that they are slidinglyassembled on the guide reentrant holes 603 and 603'.

In the first and second embodiments of the present invention, referencenumerals 92 and 902 each designate bearings which are used to rotatablyinstall the chain sprockets 9 and 90 on the shaft pipes 3 and 3a.

Under the above construction, if the pedals 7 and 7' are driven, thedistance between the pedals 7 and 7' and the crankshafts 5 and 5' isextended, to thereby achieve an optimal running energy. Now, anexplanation of an operation of the variable pedal driving deviceconstructed according to the first embodiment of the present inventionwill be in detail discussed hereinafter.

In operation, if the pedals 7 and 7' are driven, the crankshafts 5 and5' are rotated by the rotating force of the pedals 7 and 7'. At thetime, the slide pipes 8 and 8' on which the pedals 7 and 7' areassembled are slid along the crankshafts 5 and 5', such that as therotary radius between the main shaft 10 on which the crankshafts 5 and5' are installed and the pedals 7 and 7' is varied, it is extended atits maximum when the pedals 7 and 7' are rotated in the forwarddirection.

In other words, the rotary levers 4 and 4' are assembled on the shaftpipe 3 and are rotated within the same rotary radius centering aroundthe main shaft 10. The pedals 7 and 7' of the slide pipes 8 and 8'assembled on the front sides of the rotary levers 4 and 4' are rotatedcentering around the rotary shafts 61 and 61' on which the crankshafts 5and 5' are installed, such that the distance between the rotary shafts61 and 61' and the pedals 7 and 7' is extended at its maximum to therebyobtain an optimal running energy, when the pedals 7 and 7' are rotatedin the forward direction.

In more detail, if the pedals 7 and 7' are rotated in the forwarddirection, the slide pipes 8 and 8' on which the pedals 7 and 7' areassembled are guided to the crankshafts 5 and 5' assembled on the slideholes 81 and 81' and are then driven toward the forward direction. Atthe time, since the rotary shafts 61 and 61' are fixedly installed onthe rear wheel 15, the slide pipes 8 and 8' are guided by the rotarylevers 4 and 4' and are extended at its maximum on a point where themain shaft 10 is passed.

The rotary shafts 61 and 61' of the crankshafts 5 and 5', which arerotated by the driving force of the pedals 7 and 7', enable the drivingtooth wheels 62 and 62' within the cases 65 and 65' to be rotated, thusto rotate the differential tooth wheels 63 and 63' connected by means ofthe chain 67 and 67' with the driving tooth wheels 62 and 62'.

The differential tooth wheels 63 and 63' are assembled on the both endsof the main shaft 10 to transmit the driving force of the pedals 7 and7' to the rear wheel 15, and the driven tooth wheel 11 mounted on thecoaxial line on the differential tooth wheel 63' allows the rotary toothwheel 12 of the chain sprocket 9 connected by the chain 16 to berotated, such that the chain sprocket 9 is rotated to thereby drive therear wheel 15 connected by means of the chain 16 with the chain sprocket9.

The rotary radius between the crankshafts 5 and 5' and the pedals 7 and7' is extended during the driving of the pedals 7 and 7' in the forwarddirection to thereby obtain an optimal running energy.

Now, an explanation of an operation of the variable pedal driving deviceconstructed according to the second embodiment of the present inventionwill be in detail discussed hereinafter.

In operation, if the pedals 70 and 70' are driven, the rotary radiuscentering around the main shaft 10a of the crankshafts 5 and 5' on whichthe pedals 7 and 7' are slidingly assembled is varied to thereby achieveoptimal running energy.

In other words, if the pedals 70 and 70' are driven, the slide tubes 80and 80' into which the pedals 70 and 70' are assembled are coupled onthe circular disks 601 and 601' by means of the hinge shafts 66 and 66',such that they are guided to the circular disks 601 and 601'eccentrically installed on the main shaft 10a. As a result, when thepedals 70 and 70' are driven in the forward direction, the rotary radiusof them can be extended at its maximum.

In more detail, if the pedals 70 and 70' are rotated in the forwarddirection, the slide pipes 80 and 80' on which the pedals 70 and 70' areassembled enable the guide members 604 and 604' on the hinge shafts 606and 606' to be rotated along the guide reentrant holes 603 and 603' ofthe circular disks 601 and 601' eccentrically assembled on the mainshaft 10a. When the guide members 604 and 604' are driven in the forwarddirection centering around the main shaft 10a by the driving force ofthe pedals 70 and 70', the distance between the pedals 70 and 70' andthe main shaft 10a can be extended at its maximum.

Therefore, when the pedals 70 and 70' on the guide members 604 and 604'slidingly assembled on the circular disks 601 and 601' are driven from amost upper dead point to a most lower dead point, the distance betweenthe crankshafts 50 and 50' on which the pedals 70 and 70' are slidinglyassembled and the main shaft 10a is extended at its maximum to therebyachieve an optimal driving energy.

The crankshafts 50 and 50' are rotated by the driving force of thepedals 70 and 70', to thereby rotate the driving tooth wheel 607 on themain shaft 10a. Then, the rotating force of the driving tooth wheel 607is transmitted to the differential tooth wheel 608 and the driven toothwheel 609 installed on the coaxis of the differential tooth wheel 608.Finally, the rotating force of the tooth wheels 608 and 609 istransmitted to the rotary tooth wheel 901, such that the chain sprocket90 is rotated and the rear wheel 15 connected by means of the chain 16with the rotated chain sprocket 90 is thus driven.

INDUSTRIAL APPLICABILITY

As apparent from the foregoing, a variable pedal driving device of abicycle constructed according to the present invention can extend at itsmaximum the rotary radius between pedals, rotary shafts of cases as amain driving shaft of a rotating force and a main shaft of circulardisks to transmit the extended maximum rotary radius to a rear wheel,when the pedals are driven in a forward direction, thus to obtain anoptimal driving energy at the expense of a minimum physical energyconsumption.

What is claimed is:
 1. A variable pedal driving device comprising:achain sprocket mounted on a main shaft, the chain sprocket beingengageable with a chain to drive a driving wheel; a first powertransmission unit disposed to one side of the chain sprocket, the firstpower transmission unit including a first disk eccentrically mounted onthe main shaft; a second power transmission unit disposed on a side ofthe chain sprocket opposite to the first power transmission unit, thesecond power transmission unit including a second disk eccentricallymounted on the main shaft; a first crankshaft coupled to the main shaft;a first slide element slidably mounted on the first crankshaft; a firstguide member operatively connected to the first slide element, the firstguide member being translatable along a periphery of the first disk; afirst pedal operatively connected to the first slide element andslidable with said first slide element; a second crankshaft coupled tothe main shaft; a second slide element slidably mounted on the secondcrankshaft; a second guide member operatively connected to the secondslide element, the second guide member being translatable along aperiphery of the second disk; and a second pedal operatively connectedto the second slide element and slidable with said second slide element.2. The variable pedal driving device of claim 1, wherein the first powertransmission unit includes:a driving tooth wheel mounted on the mainshaft between the first crankshaft and the chain sprocket and coupledwith the first crankshaft for rotation therewith; and a differentialtooth wheel having gear teeth engaged with gear teeth of the drivingtooth wheel.
 3. The variable pedal driving device of claim 2, whereinthe first power transmission unit includes:a driven tooth wheel disposedbetween the first disk and the chain sprocket, the driven tooth wheelbeing coaxially mounted with the differential tooth wheel for rotationwith the differential tooth wheel; and a rotary tooth wheel mounted onthe main shaft for rotation with the chain sprocket, the rotary toothwheel having gear teeth engaging gear teeth of the driven tooth wheel.4. The variable pedal driving device of claim 1, wherein the first diskhas a generally circular peripheral edge.
 5. The variable pedal drivingdevice of claim 1, wherein the first slide element is pivotably coupledto the first guide member, and the first pedal is pivotably coupled tothe first slide element.
 6. The variable pedal driving device of claim5, wherein the second slide element is pivotably coupled to the secondguide member, and the second pedal is pivotably coupled to the secondslide element.
 7. The variable pedal driving device of claim 1, whereinthe first guide member includes projections which are engageable withgrooves on either side of the first disk to enable translation of thefirst guide member along the periphery of the first disk.
 8. Thevariable pedal driving device of claim 1, wherein the first pedal is atits furthest point from the main shaft when the first pedal is driven ina forward direction.
 9. A variable pedal driving device comprising:achain sprocket mounted on a main shaft, the chain sprocket beingengageable with a chain to drive a driving wheel; a first powertransmission unit disposed to one side of the chain sprocket, the firstpower transmission unit including a first disk eccentrically mounted onthe main shaft; a second power transmission unit disposed on a side ofthe chain sprocket opposite to the first power transmission unit; afirst crankshaft coupled to the main shaft; a first pedal operativelyconnected to the first disk, the first pedal being slidably mounted onthe first crankshaft, sliding of the first pedal being effected byeccentric rotation of the first disk about the main shaft; a drivingtooth wheel mounted on the main shaft between the first crankshaft andthe first disk for rotation with the first crankshaft; a differentialtooth wheel having gear teeth engaged with gear teeth of the drivingtooth wheel; a driven tooth wheel mounted coaxially with thedifferential tooth wheel for co-rotation with the differential toothwheel, the driven tooth wheel being disposed between the chain sprocketand the first disk; a rotary tooth wheel mounted on the main shaft forco-rotation with the chain sprocket, the rotary tooth wheel having gearteeth engaging gear teeth of the driven tooth wheel; a second crankshaftcoupled to the main shaft; and a second pedal slidably and pivotablycoupled to the second crankshaft.
 10. The variable pedal driving deviceof claim 9, wherein the second power transmission unit includes a seconddisk eccentrically mounted on the main shaft, sliding of the secondpedal being effected by eccentric rotation of the second disk about themain shaft.
 11. The variable pedal driving device of claim 10, furthercomprising a second slide element pivotably coupled to the second pedal,the second slide element including an aperture through which the secondcrankshaft extends and being slidable along the second crankshaft. 12.The variable pedal driving device of claim 11, further comprising asecond guide member, the second guide member being pivotably coupled tothe second slide element and being translatable along a periphery of thesecond disk.
 13. The variable pedal driving device of claim 9, furthercomprising a first slide element pivotably coupled to the first pedal,the first slide element including an aperture through which the firstcrankshaft extends and being slidable along the first crankshaft. 14.The variable pedal driving device of claim 13, further comprising afirst guide member, the first guide member being pivotably coupled tothe first slide element and being translatable along a periphery of thefirst disk, the first guide member including projections which areengageable with grooves on either side of the first disk to enabletranslation of the first guide member along the periphery of the firstdisk.
 15. The variable pedal driving device of claim 9, wherein thefirst disk has a generally circular peripheral edge.
 16. The variablepedal driving device of claim 9, wherein the first pedal is at itsfurthest point from the main shaft when the first pedal is driven in aforward direction.